vendor: add github.com/manifoldco/promptui and dependencies

vendor/github.com/golang/lint/golint/importcomment.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2018 The Go Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd.
+
+// +build go1.12
+
+// Require use of the correct import path only for Go 1.12+ users, so
+// any breakages coincide with people updating their CI configs or
+// whatnot.
+
+package main // import "golang.org/x/lint/golint"